MLA
Harris, Tucker. Letter from Dr. Tucker Harris to "My Beloved Children" Regarding His Childhood and the Genealogy of the Harris Family (Typescript). 1800. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 9, Folder 49. https://digital.library.emory.edu/purl/453wstqkqb-cor.
APA, 6th edition
Harris, T. (1800). Letter from Dr. Tucker Harris to "My Beloved Children" regarding his childhood and the genealogy of the Harris family (typescript) (Box 9, Folder 49) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/453wstqkqb-cor.
Chicago
Harris, Tucker. “Letter from Dr. Tucker Harris to ‘My Beloved Children’ Regarding His Childhood and the Genealogy of the Harris Family (Typescript).” Letters (correspondence). Civil War Collection, 1800. Box 9, Folder 49. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/453wstqkqb-cor.